Two things-
I had a click that was difficult to find, finally found a loose tension adjustment on SPD pedals. Tightened up the tension a turn or two and eliminated the problem.
I rode with a guy that was hearing a click from the bottom bracket area, but couldn't pinpoint it. A couple of weeks later, still clicking, the right crankarm fell off and pulled the RD into the spokes. Did a couple of hundred dollars worth of damage.